The invention relates generally to integrated circuits, and more particularly, to a system and method for assembling the integrated circuits for mounting them to devices or other circuit boards.
Conventional integrated circuits, or "chips," are formed from a flat surface semiconductor wafer. The semiconductor wafer is first manufactured in a semiconductor material manufacturing facility and is then provided to a fabrication facility. At the latter fabrication facility, several layers are processed onto the semiconductor wafer surface. Once completed, the wafer is then cut into one or more chips and assembled into packages.
A chip is fabricated with a plurality of bonding pads, usually made of aluminum, for connecting the chip to other devices (e.g., other chips or circuit boards). For very tight, low-profile chips, a solder bump is placed on the aluminum bonding pad and then connected directly to the other device. This technology has several variances, such as flip chip technology, tape-automated bonding, ball-grid array and so forth.
In these technologies, the device to which the chip is connecting may also include a plurality of bonding pads, which may in turn include a plurality of solder bumps. It is important that each of the pads/bumps of the chip are properly aligned with the corresponding pads/bumps of the connecting device. However, as chip size decreases, and as the number of pads/bumps increases, the margin of error for aligning these devices becomes extremely limiting.
This problem is exacerbated when multiple chips must simultaneously align for mounting. Consider for example, co-pending U.S. patent application Ser. No. 08/858,004 filed on May 16, 1997, assigned to the same assignee as the present application and hereby incorporated by reference as if reproduced in its entirety. This application describes a spherical shaped integrated circuit which may be clustered with other spherical shaped integrated circuits to form a single, large-scale device. However, it is very difficult to perform such clustering because of the tight margin of error between the devices.
Therefore, what is needed is a system and method for aligning the bonding pads or solder bumps of devices such as chips or spherical shaped integrated circuits to facilitate their connection with other devices and/or circuit boards.